Buggy code:
public ReferenceBinding [ ] memberTypes ; public TypeVariableBinding [ ] typeVariables ; public ClassScope scope ; public static final int METHOD_EMUL = 0 ; public static final int FIELD_EMUL = 1 ; public static final int CLASS_LITERAL_EMUL = 2 ; public static final int RECEIVER_TYPE_EMUL = 3 ; HashMap [ ] synthetics ; char [ ] genericReferenceTypeSignature ; public SourceTypeBinding ( char [ ] [ ] compoundName , PackageBinding fPackage , ClassScope scope ) { } private void addDefaultAbstractMethod ( MethodBinding abstractMethod ) { } public void addDefaultAbstractMethods ( ) { } public FieldBinding addSyntheticFieldForInnerclass ( LocalVariableBinding actualOuterLocalVariable ) { } public FieldBinding addSyntheticFieldForInnerclass ( ReferenceBinding enclosingType ) { } public FieldBinding addSyntheticFieldForClassLiteral ( TypeBinding targetType , BlockScope blockScope ) { } public FieldBinding addSyntheticFieldForAssert ( BlockScope blockScope ) { } public FieldBinding addSyntheticFieldForEnumValues ( ) { } public SyntheticMethodBinding addSyntheticMethod ( FieldBinding targetField , boolean isReadAccess ) { } public SyntheticMethodBinding addSyntheticEnumMethod ( char [ ] selector ) { } public SyntheticMethodBinding addSyntheticMethod ( MethodBinding targetMethod , boolean isSuperAccess ) { } public SyntheticMethodBinding addSyntheticBridgeMethod ( MethodBinding inheritedMethodToBridge , MethodBinding targetMethod ) { } public void collectSubstitutes ( Scope currentScope , TypeBinding otherType , Map substitutes , int constraint ) { } public int kind ( ) { } public char [ ] computeUniqueKey ( ) { } void faultInTypesForFieldsAndMethods ( ) { } public FieldBinding [ ] fields ( ) { } public char [ ] genericTypeSignature ( ) { } public char [ ] genericSignature ( ) { } public long getAnnotationTagBits ( ) { } public MethodBinding [ ] getDefaultAbstractMethods ( ) { } public MethodBinding getExactConstructor ( TypeBinding [ ] argumentTypes ) { } public MethodBinding getExactMethod ( char [ ] selector , TypeBinding [ ] argumentTypes , CompilationUnitScope refScope ) { } public FieldBinding getField ( char [ ] fieldName , boolean needResolve ) { } public MethodBinding [ ] getMethods ( char [ ] selector ) { } public FieldBinding getSyntheticField ( LocalVariableBinding actualOuterLocalVariable ) { } public FieldBinding getSyntheticField ( ReferenceBinding targetEnclosingType , boolean onlyExactMatch ) { } public SyntheticMethodBinding getSyntheticBridgeMethod ( MethodBinding inheritedMethodToBridge ) { } public boolean isEquivalentTo ( TypeBinding otherType ) { } public boolean isGenericType ( ) { } public ReferenceBinding [ ] memberTypes ( ) { } public FieldBinding getUpdatedFieldBinding ( FieldBinding targetField , ReferenceBinding newDeclaringClass ) { } public MethodBinding getUpdatedMethodBinding ( MethodBinding targetMethod , ReferenceBinding newDeclaringClass ) { } public boolean hasMemberTypes ( ) { } public MethodBinding [ ] methods ( ) { if ( ( ( tagBits ) & ( AreMethodsComplete ) ) != 0 ) return methods ; int failed = 0 ; try { for ( int i = 0 , length = methods . length ; i < length ; i ++ ) { if ( ( resolveTypesFor ( methods [ i ] ) ) == null ) { methods [ i ] = null ; failed ++ ; } } boolean complyTo15 = ( fPackage . environment . options . sourceLevel ) >= ( ClassFileConstants . JDK1_5 ) ; for ( int i = 0 , length = methods . length ; i < length ; i ++ ) { MethodBinding method = methods [ i ] ; if ( method != null ) { TypeBinding returnErasure = ( ( method . returnType ) == null ) ? null : method . returnType . erasure ( ) ; char [ ] selector = method . selector ; AbstractMethodDeclaration methodDecl = null ; nextMethod : for ( int j = length - 1 ; j > i ; j -- ) { MethodBinding method2 = methods [ j ] ; if ( ( method2 == null ) || ( ! ( CharOperation . equals ( selector , method2 . selector ) ) ) ) continue nextMethod ; if ( complyTo15 ) { if ( returnErasure != ( ( method2 . returnType ) == null ? null : method2 . returnType . erasure ( ) ) ) { if ( ! ( method . areParametersEqual ( method2 ) ) ) continue nextMethod ; if ( ! ( method . areTypeVariableErasuresEqual ( method2 ) ) ) <START_BUG> if ( ( ( method . typeVariables . length ) > 0 ) && ( ( method2 . typeVariables . length ) > 0 ) ) <END_BUG> continue nextMethod ; } else if ( ! ( method . areParameterErasuresEqual ( method2 ) ) ) { continue nextMethod ; } } else if ( ! ( method . areParametersEqual ( method2 ) ) ) { continue nextMethod ; } boolean isEnumSpecialMethod = ( isEnum ( ) ) && ( ( selector == ( TypeConstants . VALUEOF ) ) || ( selector == ( TypeConstants . VALUES ) ) ) ; if ( methodDecl == null ) { methodDecl = method . sourceMethod ( ) ; if ( ( methodDecl != null ) && ( ( methodDecl . binding ) != null ) ) { if ( isEnumSpecialMethod ) scope . problemReporter ( ) . duplicateEnumSpecialMethod ( this , methodDecl ) ; else scope . problemReporter ( ) . duplicateMethodInType ( this , methodDecl ) ; methodDecl . binding = null ; methods [ i ] = null ; failed ++ ; } } AbstractMethodDeclaration method2Decl = method2 . sourceMethod ( ) ; if ( ( method2Decl != null ) && ( ( method2Decl . binding ) != null ) ) { if ( isEnumSpecialMethod ) scope . problemReporter ( ) . duplicateEnumSpecialMethod ( this , method2Decl ) ; else scope . problemReporter ( ) . duplicateMethodInType ( this , method2Decl ) ; method2Decl . binding = null ; methods [ j ] = null ; failed ++ ; } } if ( ( returnErasure == null ) && ( methodDecl == null ) ) { method . sourceMethod ( ) . binding = null ; methods [ i ] = null ; failed ++ ; } } } }

Fix:
if ( ( ( method . typeVariables ) != ( NoTypeVariables ) ) && ( ( method2 . typeVariables ) != ( NoTypeVariables ) ) )